Ultrasonic pulse method for testing steel rod reinforced concrete beams

ABSTRACT

A system for non-destructive testing of a bond condition of concrete beams reinforced by steel rods is described. The system includes a transducing transmitter, a transducing receiver, and an ultrasonic pulse generator configured to generate drive signals for the transducing transmitter and receive a plurality vibrational waves at the transducing receiver. The system further includes a computing device including a measurement circuit configured to record a transit time for each vibrational wave and divide a distance between the transducing transmitter and the transducing receiver by the transit time to determine a pulse velocity of each vibrational wave, a comparison circuit configured to identify a highest pulse velocity of the vibrational waves and compare each highest pulse velocity to a first reference pulse velocity, and a decision circuit including an artificial neural network configured to identify a compromised bond condition around a steel rod.

STATEMENT OF ACKNOWLEDGEMENT

The inventor(s) acknowledge the financial support provided by theDeanship of Scientific Research (DSR) at Imam Abdulrahman Bin FaisalUniversity, IAU, Kingdom of Saudi Arabia for the financial supportfunded under project ID 2020-158-Eng.

TECHNICAL FIELD

The present disclosure is directed to a non-destructive testing methodto evaluate a bond condition of reinforced concrete beam. In particular,the present disclosure relates to non-destructive ultrasonic pulsevelocity testing method to evaluate a bond condition of reinforcedconcrete beam.

DESCRIPTION OF RELATED ART

The “background” description provided herein is for the purpose ofgenerally presenting the context of the disclosure. Work of thepresently named inventors, to the extent it is described in thisbackground section, as well as aspects of the description which may nototherwise qualify as prior art at the time of filing, are neitherexpressly or impliedly admitted as prior art against the presentinvention.

Engineering design is challenge in which engineers use various type ofmaterials is to achieve a desired structural performance. One of thefundamental components necessary to achieve the desired structuralstrength is the bond between steel and concrete in a reinforced concrete(RC) structure. Since concrete material has a high compressive strength,the bond strength in an RC structure is the ability of the steelreinforcement to resist slipping and support portions of the tensileload, thus allowing concrete material to carry the compressive force.Low bond strength leads to inadequate stress transfer resulting intensile failure of the RC member. This type of failure is categorized asbrittle or sudden failure (See: Qasrawi, H. Y. and Marie, I. A. (2013).“The use of USPV to anticipate failure in concrete under compression.”,Cement Concrete Research, 33(12), 2017-2021; Saleem, M. (2017) “Study todetect bond degradation in reinforced concrete beams using ultrasonicpulse velocity test method.”, Structural Engineering and Mechanics, AnInternational Journal, 64(4), 427-436. DOI: hypertext transfer protocol://doi.org/10.12989/sem.2017.64.4.427; Saleem, M., Blaisi N I. (2019)“Development, testing, and environmental impact assessment ofglow-in-the-dark concrete.”, Structural Concrete, Vol. 20, pp.1792-1803, 2019. DOI: hypertext transfer protocol://doi.org/10.1002/suco.201800221; Nolan C. and Andres, W. (2019).“Investigation of the effects of corrosion on bond strength of steel inconcrete using neural network”. The 2019 World Congress on Advances inStructural Engineering and Mechanics (ASEM19) Jeju Island, Korea, Sep.17-21, 2019). The bond performance is responsible for the compositebehavior and stress balance between steel and concrete. Research hasbeen conducted to understand the bond behavior of steel reinforcedconcrete by experimentation, analytical and empirical modeling (See:Guillet, T. (2011) “Behavior of metal anchors under combined tension andshear cycling loads.”, ACI Structural Journal, 108 (3), pp: 315-323;Desnerck, P, Lees, J. M., & Morley, C. T. (2015). “Bond behavior ofreinforcing bars in cracked concrete”. Construction and BuildingMaterials, 94, 126-136; Tondolo, F. (2015). Bond behaviour withreinforcement corrosion. Construction and Building Materials, 93,926-932). However, owing to the complexity of stresses at the interfaceof steel and concrete some assumptions were incorporated into the modelsin order to simplify the physical phenomenon. Hence, the true complexpicture of the non-linear stress distribution has not been thoroughlyinvestigated.

Testing of concrete beams is often .carried out to determine asuitability of a structure for its intended use. Non-destructive testingmethods are commonly used to evaluate concrete properties by assessingthe strength, quality, and other properties such as permeability,cracking, and void structure. The test results of the non-destructivetesting methods can be used to determine whether repairs should be madeto a structure or if the integrity of the structure is sufficient as is.

An ultrasonic pulse velocity tester is described in U.S. PatentApplication Publication No. US 2018/0059062 A1. “Ultrasonic pulsevelocity tester”, incorporated herein by reference in its entirety. Theultrasonic pulse velocity tester includes circuitry configured toprocess ultrasonic measurement signals. Further, the ultrasonic pulsevelocity tester includes a first probe and a second probe connected tothe circuitry. An ultrasonic signal is transmitted by the circuitrythrough the first probe and rebounded by the second probe. The circuitrydetects a time duration to receive the rebounded signal and compares thetime duration to a reference measurement data.

Ultrasonic testing of the fire resistance of construction materials isdescribed in Russian Patent Application No. RU 2707984 C1, “Method ofdetermining fire resistance of construction materials and structuralelements”. This patent application describes that When an ultrasonicwave amplitude is reduced in a material, crack formation is identified.The material is subjected to heating and an ultrasonic pulse velocitytest was conducted under different heating levels, until the materialcracked. Further, crack detection in reinforced concrete beams carriedout at negative temperatures is described in Russian Patent ApplicationNo. RU2279069 C1, “Mode of ultrasound control in the process ofexploitation of concrete and reinforced concrete constructions oferections for availability of deep cracks”. Also, a non-contactinspection system is described in U.S. Patent Application PublicationNo. 200.2/0184950 A1, “Non-contact inspection system for large concretestructures”, incorporated herein by reference in its entire This patentapplication described testing of large concrete structures such as dams,in which a laser transmitter-receiver is modulated by the acoustic wave.

In addition to the above research, a study of ultrasonic pulse velocityon plain and reinforced damaged concrete is described. (See: “The studyof ultrasonic pulse velocity on plain and reinforced damaged concrete”,Mataram University Kumamoto University).

Artificial neural networks (ANN) are based on the concept of human brainneural network, since human brain is a highly complex, non-linearparallel computer consisting of neurons responsible for undertakingsimultaneous multiple tasks. ANNs are also composed of similarstructures with several neurons that are excellent for patternrecognition, prediction, classification, categorization. The fundamentalbenefit of using ANN over traditional analytical modeling is the lack ofneed to make simplification assumptions. By adopting ANN, researchershave been able recognize patterns in complex non-linear problems.However, the fundamental drawback of using ANNs is the need of largeamounts of training data necessary to avoid overfitting andunderfitting.

None of the systems and methods described above have the capability toinvestigate bond condition along lengths of embedded steel rods inreinforced concrete beams under different mechanical stress loads.

Accordingly, it is one object of the present disclosure to providesystems and methods for investigation of bond condition along lengths ofembedded steel rods in reinforced concrete beams under differentmechanical stress loads and to identify the width of cracks formedaround the bonds.

SUMMARY

In an exemplary embodiment, a method for non-destructive testing of abond condition of concrete beams reinforced by steel rods is described,including applying, by a transmitting transducer of an ultrasonictester, ultrasonic pulses to a concrete beam; receiving, by anultrasonic receiver, vibrational waves reflected from the steel rods ata plurality of reading locations along the concrete beam; measuring atransit time of the vibrational waves received at each reading location;determining a pulse velocity of each vibrational wave received at eachreading location; determining a highest pulse velocity of thevibrational waves at each reading location; comparing the highest pulsevelocity of the vibrational waves received at a reading location to afirst reference pulse velocity; and identifying a bond condition ofcracking around a steel rod at a testing location when the highest pulsevelocity at the testing, location is less than the first reference pulsevelocity.

In another exemplary embodiment, a non-destructive ultrasonic testingmethod of the bond condition of a concrete beam reinforced by steel rodsis described, including applying, by a transmitting transducer of anultrasonic tester, ultrasonic pulses to a concrete beam; receiving, byan ultrasonic receiver, vibrational waves reflected from the steel rodsat a plurality of reading locations along the concrete beam; measuring atransit time of the vibrational waves received at each reading location;determining a pulse velocity of each vibrational wave received at eachreading location; determining a highest pulse velocity of thevibrational waves at each reading location, the highest pulse velocityat each reading location defining a first reference pulse velocity atthe reading location; determining a peak load carrying capacity(P_(peak)) of the concrete beam by applying a force perpendicular to acenter of a length of the concrete beam; applying a second set ofultrasonic pulses to the concrete beam; measuring a highest pulsevelocity at each reading location received from the second set ofultrasonic pulses; increasing a magnitude of the force by increments;measuring a highest pulse velocity at each reading location for eachincremental increase in the magnitude of the force; determining theP_(peak) of the concrete beam when the highest pulse velocity at one ofthe reading locations is less than a second reference pulse velocity,where the second reference pulse velocity is less than the firstreference pulse velocity.

In yet another exemplary embodiment, a system for non-destructivetesting of the bond condition of concrete beams reinforced by steel rodsis described, including a transducing transmitter; a transducingreceiver; an ultrasonic pulse generator configured to generate drivesignals for the transducing transmitter and receive a pluralityvibrational waves at the transducing receiver; a computing deviceincluding a measurement circuit configured to record a transit time foreach vibrational wave and divide a distance between the transducingtransmitter and the transducing receiver by the transit time todetermine a pulse velocity of each vibrational wave; a comparisoncircuit configured to identify a highest pulse velocity of thevibrational waves and compare each highest pulse velocity to a firstreference pulse velocity; and a decision circuit configured to identifya compromised bond condition around a steel rod when the highest pulsevelocity is less than the first reference pulse velocity.

The foregoing general description of the illustrative embodiments andthe following detailed description thereof are merely exemplary aspectsof the teachings of this disclosure, and are not restrictive.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete appreciation of this disclosure and many of theattendant advantages thereof will be readily obtained as the samebecomes better understood by reference to the following detaileddescription when considered in connection with the accompanyingdrawings, wherein:

FIG. 1 is a schematic diagram of a system for non-destructive testing ofbond condition of concrete beams reinforced by steel rods, according toexemplary aspects of the present disclosure;

FIG. 2 illustrates a method of identifying a bond condition of aconcrete beam based on a first reference pulse velocity, according toexemplary aspects of the present disclosure;

FIGS. 3A and 3B illustrate a method of identifying a bond condition of aconcrete beam based on a second reference pulse velocity, according toexemplary aspects of the present disclosure;

FIG. 4 shows concrete beam samples and concrete cylinder specimensevaluated using an ultrasonic pulse velocity (UPV) testing method,according to exemplary aspects of the present disclosure;

FIG. 5 shows steel reinforcements and shear reinforcements of a concretebeam sample, according to exemplary aspects of the present disclosure;

FIG. 6 shows curing of the concrete beam samples, according to exemplaryaspects of the present disclosure;

FIG. 7 depicts a conceptual diagram of a concrete beam sample evaluatedusing the UPV testing method, according to exemplary aspects of thepresent disclosure;

FIG. 8 shows reading locations along a length of a steel reinforcementof a concrete beam sample, according to exemplary aspects of the presentdisclosure;

FIG. 9 illustrates an UPV test setup for a concrete beam sample,according to exemplary aspects of the present disclosure;

FIG. 10 illustrates factors affecting bond performance of the concretebeam samples, according to exemplary aspects of the present disclosure;

FIG. 11 illustrates a graphical representation of test results for theUPV testing method on the concrete beam samples, according to exemplaryaspects of the present disclosure;

FIG. 12 illustrates a graphical representation showing the decrease inthe pulse velocity with the increase in the applied loading, accordingto exemplary aspects of the present disclosure;

FIG. 13 illustrates a graphical representation of reduction in pulsevelocity with the increase in the applied loading in the concrete beamsamples, according to exemplary aspects of the present disclosure;

FIG. 14 illustrates a graphical representation of variation pulsevelocity, along the length of steel reinforcement, according toexemplary aspects of the present disclosure;

FIG. 15 illustrates a graphical representation of reduction in pulsevelocity reading after the application of loading increment for topzone, according to exemplary aspects of the present disclosure;

FIG. 16 illustrates a graphical representation of variation in the pulsevelocity after the application of loading, according to exemplaryaspects of the present disclosure;

FIG. 17 illustrates a graphical representation of variation in the pulsevelocity with increase in applied loading, according to exemplaryaspects of the present disclosure;

FIG. 18A illustrates a cross-sectional view of a cracking pattern for aconcrete beam sample, according to exemplary aspects of the presentdisclosure;

FIG. 18B illustrates a side view of the cracking pattern for theconcrete beam sample, according to exemplary aspects of the presentdisclosure;

FIG. 18C illustrates a bottom view of the cracking pattern for theconcrete beam sample, according to exemplary aspects of the presentdisclosure;

FIG. 18D illustrates a cross-sectional view of a cracking pattern for aconcrete beam sample, according to exemplary aspects of the presentdisclosure;

FIG. 18E illustrates a bottom view of the cracking pattern for theconcrete beam sample, according to exemplary aspects of the presentdisclosure;

FIG. 18F illustrates a side view of the cracking pattern for theconcrete beam sample, according to exemplary aspects of the presentdisclosure;

FIG. 19 illustrates the architecture of a feed-forward artificialmulti-layer perceptron network

FIG. 20 shows a chart depicting single neuron's activity, according toexemplary aspects of the present disclosure;

FIG. 21 illustrates a flowchart diagram of the feed-forward artificialmulti-layer perceptron network, according to exemplary aspects of thepresent disclosure;

FIG. 22 illustrates an FFMLP-4-3-1 three-layered feed-forward artificialneural network, according to exemplary aspects of the presentdisclosure;

FIG. 23 is a graph of the normalized importance of influence parameters,according to exemplary aspects of the present disclosure;

FIG. 24 is a graph of the variation in compressive strength with respectto UPV, according to exemplary aspects of the present disclosure;

FIG. 25 is a graph of the predicted crack width with respect to theexperimental crack width, according to exemplary aspects of the presentdisclosure;

FIG. 26 is an illustration of a non-limiting example of details ofcomputing hardware used in the computing system, according to exemplaryaspects of the present disclosure;

FIG. 27 is an exemplary schematic diagram of a data processing systemused within the computing system, according to exemplary aspects of thepresent disclosure;

FIG. 28 is an exemplary schematic diagram of a processor used with thecomputing system, according to exemplary aspects of the presentdisclosure; and

FIG. 29 is an illustration of a non-limiting, example of distributedcomponents which may share processing with the controller, according toexemplary aspects of the present disclosure;

DETAILED DESCRIPTION

In the drawings, like reference numerals designate identical orcorresponding parts throughout the several views. Further, as usedherein, the words “a,” “an” and the like generally carry a meaning of“one or more,” unless stated otherwise.

Furthermore, the terms “approximately,” “approximate,” “about,” andsimilar terms generally refer to ranges that include the identifiedvalue within a margin of 20%, 10%, or preferably 5%, and any valuestherebetween.

Aspects of this disclosure are directed to systems and methods fornon-destructive ultrasonic testing of the bond condition of concretebeams reinforced by steel rods.

FIG. 1 is a schematic diagram of a system 100 for non-destructivetesting of bond condition of concrete beams reinforced by steel rods,according to exemplary aspects of the present disclosure.

According to an aspect of the present disclosure, the system 100 may beconfigured to perform an ultrasonic pulse velocity (UPV) test toevaluate the quality and strength of reinforced concrete beams.

Referring to FIG. 1 , the system 100 (also referred to as ultrasonictester 100) may include an ultrasonic pulse generator 102, a transducingtransmitter 104 (also referred to as a transmitting transducer 104), atransducing receiver 106 (also referred to as a receiving transducer106), a computing device 108, and a peak load testing device 110. Thecomputing device 108 may further include a measurement circuit 112, acomparison circuit 114, and a decision circuit 116. The peak loadtesting device 110 may further include a first support 118, a secondsupport 120, and a force applicator 122.

In an aspect of the present disclosure, the ultrasonic pulse generator102 may be any device that may be configured to generate a plurality ofdrive signals (or electrical signals) to excite the transducingtransmitter 104. In an example, the plurality of drive signals may behigh voltage signals. According to an aspect, the transducingtransmitter 104 may be configured to. convert the plurality of drivesignals into a plurality of ultrasonic pulses. When the plurality ofultrasonic pulses is applied to concrete beams by the transducingtransmitter 104, the plurality of ultrasonic pulses may undergo multiplereflections at the surfaces of the concrete beams, and may reflect backto the transducing receiver 106. In an example, the transducingtransmitter 104 and the transducing receiver 106 may be configured tooperate at a frequency range of about 20 kHz to about 150 kHz. Also, inan example, the transducing transmitter 104 and the transducing receiver106 may be piezoelectric transducers, capacitive transducers,magnetostrictive transducers, or any other suitable type of transducers.

Referring back to FIG. 1 , the computing system 108 may be a desktopcomputer, a laptop, a tablet computer, a mobile device, a PersonalDigital Assistant (PDA) or any other computing device. The computingsystem 108 may be communicatively coupled to the ultrasonic pulsegenerator 102, the transducing transmitter 104, the transducing receiver106, and the peak load testing, device 110. In an example, thecomputing, system 108 may control and monitor the functioning of theultrasonic pulse generator 102, the transducing transmitter 104, thetransducing receiver 106, and the peak load testing device 110.

According to an aspect of the present disclosure, to perform a UPV teston a concrete beam, the transducing transmitter 104 and the transducingreceiver 106 may be attached to the concrete beam. In an example, thetransducing transmitter 104 and the transducing receiver 106 may beplaced on either side of the concrete beam. For example, the transducingtransmitter 104 and the transducing receiver 106 may be attached onopposite sides of the concrete beam.

The concrete beam may be reinforced by a plurality of steel rods.Although the disclosed system 100 is applicable to the concrete beamshaving more than two rods, the description hereinafter is explained withrespect to two steel rods, namely a first steel rod and a second steelrod. According to an aspect of the present disclosure, the first steelrod may be placed at a top of the concrete beam, and the second steelrod may be placed at a bottom of the concrete beam. The first steel rodand the second steel rod may collectively be referred to as steel rods.

In an aspect of the present disclosure, the concrete beam may be markedwith a grid having a plurality of rows and a plurality of columns. In anexample, the concrete beam may be marked with the grid using guidewires. The concrete beam may be marked with a grid having two rows,namely a first row and a second row, and nine columns. The first row maybe parallel to and separated from the second row by a distance in arange of about 140 mm to about 160 mm. Further, each column may beparallel to an adjacent column and separated from the adjacent column bya distance in a range of about 90 mm to about 110 mm. Further, aplurality of reading locations may be marked on the first row parallelto a length of the first steel rod within the concrete beam, and aplurality of reading locations may be masked on the second row parallelto a length of the second steel rod within the concrete beam. In anexample, an intersection of a row with a column may define a readinglocation.

According to an aspect of the present disclosure, the transducingtransmitter 104 may contact the concrete beam at each of the pluralityof reading locations and the transducing receiver 106 may be attached tothe concrete beam at a location perpendicular to a length of the steelrods. To ensure that the plurality of ultrasonic pulses generated at thetransducing transmitter 104 passes into the concrete beam and getsdetected by the transducing receiver 106, adequate coupling between theconcrete beam, the transducing transmitter 104, and the transducingreceiver 106 may be required. In an example, the transducing transmitter104 and the transducing receiver 106 may be attached to the concretebeam using petroleum gel or any other suitable coupling means.

In an aspect of the present disclosure, to initiate the UPV test on theconcrete beam, the ultrasonic pulse generator 102 may be configured togenerate the plurality of drive: signals for the transducing transmitter104. The transducing transmitter 104 may be configured to convert theplurality of drive signals into the plurality of ultrasonic pulses.Further, the transducing receiver 104 may be configured to apply a firstset of ultrasonic pulses to the concrete beam. When the first set ofultrasonic pulses are applied to the concrete beam, a plurality ofvibrational waves may be reflected from the steel rods at the pluralityof reading locations along the concrete beam. In an aspect, thetransducing receiver 106 may be configured to receive the plurality ofvibrational waves reflected from the steel rods at the plurality ofreading locations along the concrete beam. The plurality of vibrationalwaves may be referred to as vibrational waves hereinafter.

The measurement circuit 112 may be configured to record or measure atransit time (denoted by T) of each vibrational wave received at eachreading location. Further, the measurement circuit 112 may be configuredto determine a pulse velocity (denoted by V) of each vibrational wavereceived at each reading location. In an example, a pulse velocity of avibrational wave may be determined based on a path length of thevibration wave. In an aspect, the measurement circuit 112 may beconfigured to determine a pulse velocity of a vibrational wave at areading location by dividing a distance between the transducing,receiver 106 from the reading location by the transit time of thevibrational wave received at the reading location.

The comparison circuit 114 may be configured to identify or determine ahighest pulse velocity of the vibrational waves at each readinglocation. Further, the comparison circuit 114 may be configured tocompare each highest pulse velocity to a first reference pulse velocity.In an aspect of the present disclosure, the first reference pulsevelocity may be predefined. In an example, a value of the firstreference pulse velocity may be about 6500 m/s.

According to an aspect of the present disclosure, the decision circuit116 may identify a compromised bond condition of cracking around thesteel rods at a testing location when the highest pulse velocity is lessthan the first reference pulse velocity. In an example, the testinglocation may refer to one of the plurality of reading locations. Whenthe highest pulse velocity is more than the first reference pulsevelocity, this may be indicative of an acceptable bond condition andquality.

In an aspect of the present disclosure, the first support 118 may beconfigured to support a first bottom end of the concrete beam, and thesecond support 120 may be configured to support a second bottom end ofthe concrete beam. The force applicator 122 may be configured to providea variable force to a top centre of the concrete beam. In an example,the force applicator 122 is a device for applying a controlled force ata point of contact (for example, the top centre) on the concrete beam.

The measurement circuit 112 may be configured to record measurements ofpulse velocities at the plurality of reading locations for each changein the variable force. Also, the measurement circuit 112 may beconfigured to determine a second reference pulse velocity at eachreading location by measuring the highest pulse velocity when the forceapplied to the concrete beam is 75% of a peak load carrying capacity(P_(peak)) of the concrete beam. According to an aspect of the presentdisclosure, the measurement circuit 112 may determine the P_(peak) ofthe concrete beam by applying, a force perpendicular to a centre of alength of the concrete beam. In an aspect, the comparison circuit 114may be configured to determine the first reference pulse velocity ateach reading location by measuring the highest pulse velocity when theforce applied to the concrete beam is zero.

In an aspect of the present disclosure, the transducing transmitter 104may be configured to apply a second set of ultrasonic pulses to theconcrete beam. Further, the comparison circuit 114 may be configured todetermine a highest pulse velocity at each reading location receivedfrom the second set of ultrasonic pulses. The force applicator 122 mayfurther be configured to increase a magnitude of the force by incrementsand measure the highest pulse velocity at each reading location for eachincremental increase in the magnitude of the force. In an example, theforce applicator 122 may be configured to increase the magnitude of theforce in equal increments of 10 percent.

According to an aspect, the measurement circuit 112 may determine theP_(peak) of the concrete beam when the highest pulse velocity at one ofthe reading locations is less than the second reference pulse velocity.In an example, the second reference pulse velocity may be less than thefirst reference pulse velocity. In an example, a value of the secondreference pulse velocity may be about 5000 m/s.

Further, the comparison circuit 114 may be configured to compare thehighest pulse velocity of the vibrational waves received at each readinglocation to the second reference pulse velocity. In an aspect, thedecision circuit 116 may identify an amplitude of the variable force atwhich the highest pulse velocity is less than the second reference pulsevelocity. In an example, the second reference pulse velocity mayindicate a bond condition of cracking of the concrete beam around thesteel rods. The decision circuit 116 may identify the bond condition ofcracking around the steel rods at the testing location when the highestpulse velocity at the testing location is less than the second referencepulse velocity. When the highest pulse velocity is more than the secondreference pulse velocity, this may be indicative of an acceptable bondcondition and quality.

FIG. 2 illustrates a method 200 of identifying a bond condition of aconcrete beam based on a first reference pulse velocity, according toexemplary aspects of the present disclosure.

At step 202, the method 200 includes applying ultrasonic pulses to aconcrete beam reinforced by steel rods. According to aspects of thepresent disclosure, the transmitting transducer 104 may be configured toapply ultrasonic pulses to the concrete beam.

At step 204, the method 200 includes receiving vibrational wavesreflected from the steel rods at a plurality of reading locations alongthe concrete beam. In an example, when the ultrasonic pulses are appliedto the concrete beam, the vibrational waves may be reflected from thesteel rods at the plurality of reading locations along the concretebeam. According to aspects of the present disclosure, the receiving.transducer 106 may be configured to receive the vibrational wavesreflected from the steel rods at the plurality of reading locationsalong the concrete beam.

At step 206, the method 200 includes measuring a transit time of thevibrational waves received at each reading location. In an aspect of thepresent disclosure, the measurement circuit 112 may be configured tomeasure the transit time of each vibrational wave received at eachreading location.

At step 208, the method 200 includes determining a pulse velocity ofeach vibrational wave received at each reading, location. According toaspects of the present disclosure, the measurement circuit 112 may beconfigured to determine the pulse velocity of each vibrational wavereceived at each reading location. In an aspect, the measurement circuit112 may be configured to determine a pulse velocity of a vibrationalwave at a reading location by dividing a distance between the receivingtransducer 106 from the reading location by the transit time of thevibrational wave received at the reading location.

At step 210, the method 200 includes determining a highest pulsevelocity of the vibrational waves at each reading location. According toan aspect of the present disclosure, the comparison circuit 114 may beconfigured to determine the highest pulse velocity of the vibrationalwaves at each reading location.

At step 212, the method 200 includes comparing the highest pulsevelocity of the vibrational waves received at a reading location to afirst reference pulse velocity. According to aspects of the presentdisclosure, the comparison circuit 114 may be configured to compare eachhighest pulse velocity to a first reference pulse velocity. In anexample, a value of the first reference pulse velocity may be about 6500m/s.

At step 214, the method 200 includes identifying a bond condition ofcracking around a steel rod at a testing location when the highest pulsevelocity at the testing location is less than the first reference pulsevelocity. In an example, the testing location may refer to one of theplurality of reading locations. According to an aspect of the presentdisclosure, the decision circuit 116 may identify a compromised bondcondition of cracking around the steel rods at the testing location whenthe highest pulse velocity is less than the first reference pulsevelocity.

FIGS. 3A and 3B illustrate a method 300 of identifying a bond conditionof a concrete beam based on a second reference pulse velocity, accordingto exemplary aspects of the present disclosure.

At step 302, the method 300 includes applying a first set of ultrasonicpulses to a concrete beam. According to aspects of the presentdisclosure, the transmitting transducer 104 may be configured to applythe first set of ultrasonic pulses to the concrete beam.

At step 304, the method 300 includes receiving vibrational wavesreflected from the steel rods at a plurality of reading locations alongthe concrete beam. According to aspects of the present disclosure, thereceiving transducer 106 may be configured to receive the vibrationalwaves reflected from the steel rods at the plurality of readinglocations along the concrete beam.

At step 306, the method 300 includes measuring a transit time of thevibrational waves received at each reading location. In an aspect of thepresent disclosure, the measurement circuit 112 may be configured tomeasure the transit time of each vibrational wave received at eachreading location.

At step 308, the method 300 includes determining a pulse velocity ofeach vibrational wave received at each reading location. According toaspects of the present disclosure, the measurement circuit 112 may beconfigured to determine the pulse velocity of each vibrational wavereceived at each reading location. In an aspect, the measurement circuit112 may be configured to determine a pulse velocity of a vibrationalwave at a reading location by dividing a distance between the receivingtransducer 106 from the reading location by the transit time of thevibrational wave received at the reading location.

At step 310, the method 300 includes determining a highest pulsevelocity of the vibrational waves at each reading location. In anexample, the highest pulse velocity at each reading location defines afirst reference pulse velocity at the reading location. In an example, avalue of the first reference pulse velocity may be about 6500 m/s.According to an aspect of the present disclosure, the comparison circuit114 may be configured to determine the highest pulse velocity of thevibrational waves at each reading location.

At step 312, the method 300 includes determining a peak load carryingcapacity (P_(peak)) of the concrete beam by applying a forceperpendicular to a center of a length of the concrete beam. According toaspects of the present disclosure, the force applicator 122 may beconfigured to apply the force perpendicular to the center of the lengthof the concrete beam to determine the P_(peak) of the concrete beam.

At step 314, the method 300 includes applying a second set of ultrasonicpulses to the concrete beam. According to aspects of the presentdisclosure, the transmitting transducer 104 may be configured to applythe second set of ultrasonic pulses to the concrete beam.

At step 316, the method 300 includes measuring the highest pulsevelocity at each reading location received from the second set ofultrasonic pulses. According to aspects of the present disclosure, thecomparison circuit 114 may be configured to determine the highest pulsevelocity at each reading location received from the second set ofultrasonic pulses.

At step 318, the method 300 includes increasing a magnitude of the forceby increments. In an example, the magnitude of the force may beincreased in equal increments of 10 percent. According to an aspect ofthe present disclosure, the force applicator 122 may be configured toincrease the magnitude of the force by increments.

At step 320, the method 300 includes measuring the highest pulsevelocity at each reading location for each incremental increase in themagnitude of the force, in aspect of the present disclosure, thecomparison circuit 114 may be configured to measure the highest pulsevelocity at each reading location for each incremental increase in themagnitude of the force.

At step 322, the method 300 includes determining the P_(peak) of theconcrete beam when the highest pulse velocity at one of the readinglocations is less than a second reference pulse velocity. In an example,the second reference pulse velocity is less than the first referencepulse velocity. In an example, a value of the second reference pulsevelocity may be about 5000 m/s. According to an aspect, the measurementcircuit 112 may determine the P_(peak) of the concrete beam when thehighest pulse velocity at one of the reading locations is less than thesecond reference pulse velocity.

At step 324, the method 300 includes comparing the highest pulsevelocity of the vibrational waves received at a reading location to thesecond reference pulse velocity. In an aspect, the comparison circuit114 may be configured to compare the highest pulse velocity of thevibrational waves received at each reading location to the secondreference pulse velocity.

At step 326, the method 300 includes identifying a bond condition ofcracking around a steel rod at a testing location when the highest pulsevelocity of the vibrational waves at the testing location is less thanthe second reference pulse velocity. In an aspect, the decision circuit116 may identify the bond condition of cracking around the steel rods atthe testing location when the highest pulse velocity at the testinglocation is less than the second reference pulse velocity. When thehighest pulse velocity is more than the second reference pulse velocity,this may be indicative of an acceptable bond condition and quality.

Examples and Experiments

The following examples are provided to illustrate further and tofacilitate the understanding of the present disclosure.

Experimental Data and Analysis

A detailed experimental research was conducted by testing four identicalconcrete beam samples using an UPV testing method. An objective of theexperiment was to use the UPV testing method to investigate a bondcondition along the length of steel reinforcements embedded in theconcrete beam samples. A delay in ultrasonic wave transit time for thefixed path length was considered to identify the onset of internalcracking in the concrete beam samples. Further, the objective of theexperiment was to identify delay in ultrasonic wave propagation withinitiation and development of internal cracks in the concrete beamsamples.

The four identical concrete beam samples of size 150×150×1000 mm werecast using Type 1 Ordinary Portland Cement (OPC). The concrete beamsamples were cast along with six concrete cylinder specimens of 100 mmdiameter and 200 mm height for testing the comprehensive strength of theconcrete beam samples. The OPC is a basic ingredient of concrete,mortar, stucco, and non-specialty grout. The air content of the mortaramounted to 6.1% by volume and initial and final setting time wasrecorded using a Vicat apparatus as 160 and 240 mins, respectively. Thespecific gravity of OPC was 3.1. Fine aggregate was substituted usingdesert sand which consisted of water absorption of 0.83% and specificgravity of 2.57, while limestone was used as coarse aggregate withmaximum diameter of 18 mm following the gradation curve as specifiedunder ASTM C33. Bulk specific gravity and water absorption of limestonecoarse aggregate was of 2.37 and 1.95%, respectively. A water-to-cementratio of the concrete was set at 0.38 with a fine to coarse aggregateratio as 0.59 by mass. A slump reading of concrete was recorded as 100mm and polycarboxylate ether was used as superplasticizer by 0.7% weightof cement. The four concrete beam samples and the concrete cylinderspecimens that were evaluated using the UPV testing method are shown inFIG. 4 . The four concrete beam samples include a first concrete beam402, a second concrete beam 404, a third concrete beam 406, and a fourthconcrete beam 408. Further, the six cylinder specimens include a firstcylinder specimen 410, a second cylinder specimen 412, a third cylinderspecimen 414, a fourth cylinder specimen 416 a fifth cylinder specimen418, and a sixth cylinder specimen 420.

Further, steel reinforcements including two steel rods of 10 mm diameterand two steel rods of 15 mm diameter were used as compression andtension reinforcements, respectively. Also, shear stirrup reinforcementof 10 mm diameter with center-to-center spacing of 80 mm were used toarrest shear cracks from the ultrasonic wave propagation. The concretebeam samples were designed to fail in flexure to allow for verticalcracks to develop greater than shear cracks. The flexure failure assistsin identifying delay in ultrasonic wave propagation with the initiationand development of internal cracks in the concrete beam samples. Thesteel reinforcements (i.e., the tension and compression reinforcements)and shear reinforcements used in a concrete beam sample are shown inFIG. 5 . As can be seen in FIG. 5 , the concrete beam sample includessteel reinforcements 502 and shear reinforcements 504.

Each concrete beam sample was divided into two zones, namely a top zoneand a bottom zone based on the variation in steel reinforcementdiameter. The bottom zone included two 15 mm diameter steelreinforcement and 10 min diameter shear stirrup reinforcement. The topzone included two 10 mm diameter steel reinforcement along with 10 mmdiameter shear stirrup reinforcement. The concrete beam samples weredivided into the top and bottom zones to conduct the UPV testing methodfor the two types of steel reinforcements. Further, the objective ofusing steel reinforcements of two different diameter was to judge thevariation in ultrasonic wave propagation velocity for the fixed pathlength.

After the concrete beam samples were cast, the concrete beam sampleswere cured in a water tank for 28 days and then placed outside the watertank with wet jute bags covered with a plastic sheet in atemperature-controlled laboratory at 25° C.±3° C. During theexperimental research, standard practice for casting and curing ofconcrete beam samples as specified by American Society Of Testing AndMaterial (ASTM) C192 technical specifications was adhered in order toachieve consistency and assure quality of the concrete beam samples.Further, the cylinder specimens were tested as per ASTM C39 technicalspecifications to ensure quality and uniformity of test protocol. Thecylinder specimens were tested by applying uniform axial loading on toptill the concrete beam samples reached failure. The average compressivestrength was recorded as 30.95 MPa with a coefficient of variation of1.6% which is within the acceptable limit of 3.2%. FIG. 6 shows curing600 of the concrete beam samples.

In the present disclosure, the cylinder specimens closely represent thereal-world beam member. An artificial neural network (ANN) takes intoconsideration the mechanical and material parameters of the testspecimen for predicting the crack width and performing sensitivityanalysis of various parameters that affect the bond performance. FIG. 7depicts the conceptual schematic diagram of the experiment. It can bevisualized that for perfect uncracked bond condition the ultra-sonicpulse passes through the RC beam element width. As the loading isincreased, the beam undergoes micro-cracking at the steel-concreteinterface. This leads to delay in the ultra-sonic pulse to travel thefixed path length. This phenomenon identifies the location of crackedconcrete along the length of steel reinforcement. The RC beam elementhas been divided into two zones, a top zone consisting of two 14 mmsteel reinforcements and bottom zone consisting, of three 16 mm Φ steelreinforcements and a shear stirrup reinforcement consisting of 10 mm Φbars with center to center spacing of 100 mm was used. The crack widthwas also measured during the experimentation. An artificial feed-forwardperceptron neural network was developed to predict the crack width andgood agreement was found between the experimental evidence and predictedvalues using ANN. Past research in this area was focused on using UPVtest to predict concrete strength, however, the present disclosure isfocused on using UPV test to allow field engineers to identify areas ofpoor bond along the length of steel reinforcement embedded in RCmembers. This technique can be adopted for continued monitoring ofstructures and for establishing a benchmark for new structures. Fieldengineers using, this technique can quickly isolate areas for repairs incase of damage owing to natural or man-made causes, thereby reducingtime, cost and effort needed for maintenance of infrastructureutilities.

As shown in FIG. 7 , the transducing transmitter 704 and the transducingreceiver 706 were attached to the concrete beam sample 702 on eitherside of the concrete beam sample 702. The concrete beam sample 702 wastested by applying gradually increasing loading in constant intervals.Further, the ultrasonic wave readings were recorded at each stage ofloading. Through the delay in an ultrasonic wave 708 to travel the samepath length, the initiation and development of internal cracking wasascertained.

The bond condition of steel reinforcement embedded in the concrete beamsample 702 was evaluated by relating the pulse velocity of theultrasonic wave 708 to the presence of a crack (for example, amicro-crack) in the vicinity of steel reinforcement. It was identifiedthat there was delay in time for the Ultrasonic wave 708 to travel thefixed path length caused by initiation, development, and propagation ofinternal cracks. The delay in ultrasonic wave 708 to travel the fixedpath length before and after the application of external loading wasattributed to the presence of cracks in the concrete beam sample. Directand semi-direct method of investigation were used in the UPV testingmethod and areas of bond degradation owing to crack initiation,development, and propagation were identified. This led to the assessmentof bond condition along the length of steel reinforcement.

To allow ease of placement of the transducing transmitter 704 and thetransducing receiver 706 on the concrete beam samples, the steelreinforcements at the top zone of the concrete beam sample were coveredwith top cover and steel reinforcements at the bottom zone were coveredwith bottom cover. The value or size of the covers were selected toallow ease of placement of the transducing transmitter 704 and thetransducing receiver 706 on the sides of concrete beam samples. Further,guide wires were installed on the shear stirrup reinforcements of theconcrete beam samples to allow for identification of their location. Theguide wires facilitated in identifying junctions where the steelreinforcements interact with the shear stirrup reinforcements. Eachjunction may be referred to as a reading location. Further, nine readinglocations were marked that were used to take the ultrasonic wavereadings along the length of the concrete beam samples. FIG. 8 showsreading locations 802 along a length of a steel reinforcement of aconcrete beam sample 800.

FIG. 9 illustrates an UPV test setup 900 for a concrete beam sample 908.The UPV testing method was adopted to investigate the quality of bondcondition of steel reinforcement embedded into the concrete beam sample908. As can be seen in FIG. 9 , the transducing receiver 904 and thetransducing receiver 906 were attached to the concrete beam sample 908.The frequency of the transducing receiver 904 and the transducingreceiver 906 was selected to be 60 kHz. Further, nine readings wererecorded along a length of steel reinforcement embedded in the concretebeam sample 908. The readings were recorded at a top zone and a bottomzone of the concrete beam sample 908. The pulse velocity of theultrasonic waves was recoded six times at each reading location. The UPVtesting method was employed in periodic cycles to assess the degradationin strength and quality of the concrete beam sample 908. The time forultrasonic wave propagation through the width of the concrete beamsample 908 was recorded in microseconds and the ultrasonic wave velocitywas calculated by dividing the path length with the transit time. Thereadings were first recorded using a direct method of testing in aneutral condition, i.e., without application of any external loading.The readings recorded in the neutral condition served as a benchmark forthe remaining testing. Through the analysis of the recorded readings,weak spots in the bond could be identified along the length of the steelreinforcement embedded in the concrete beam sample. ASTM C597 technicalspecifications were adhered to record the readings using a direct methodof testing.

Two concrete beam samples were tested under flexure loading using ASTMC293-02 technical specifications to estimate the P_(peak) of theconcrete beam samples. The P_(peak) was used to perform further testingon the remaining two concrete beam samples. The concrete beam sampleswere tested by gradually increasing the applied loading. The load wasincreased in equal increments of 10%. It was observed that the reductionin ultrasonic pulse velocity begins to occur when load level reaches toapproximately 10% of the P_(peak). When the load level reaches toapproximately 10%, the ultrasonic pulse velocity continues to decreasewith the increase in applied loading. This phenomenon can be attributedto crack development, bridging and propagation till the P_(peak) isreached. The average value of the P_(peak) for the two concrete beamsamples was recorded as 107.2 KN. In the experimental research, theultrasonic pulse velocity test results are reported 25% of the P_(peak)at 26.8 KN, 50% of the P_(peak) at 53.6 KN, 75% of the P_(peak) at 80.4KN, and lastly at 100% of the P_(peak).

FIG. 10 illustrates factors that affect the bond performance of theconcrete beam samples, according to exemplary aspects of the presentdisclosure.

The factors that affect the bond performance of the concrete beamsamples may include steel rib width 1002 (denoted as i), steel ribspacing 1004 (denoted as j), steel rib height 1006 (denoted as k), andsteel rib angle: 1008 (denoted as Φ). Furthermore, factors such as steelreinforcement diameter, its cover along with quality of concrete werealso taken into consideration. As described earlier, as the appliedloading increases, the concrete surrounding the steel reinforcementstarts to crack, resulting in degradation of the bond. Further, thedegradation of the bond was not uniform along, the length of the steelbar. Some areas where the micro-cracks bridged and propagated showed alarger reduction in pulse velocity whereas other areas wheremicro-cracks were less prominent showed a lower percentage of pulsevelocity degradation. Thus, the bond quality along the length of steelreinforcement was assessed.

In order to eradicate human errors and to standardize the testingprotocol, ASTM C597 (2003) technical specifications was followed for alltesting. Factors such as concrete strength, age, maximum aggregate size,type of cement, moisture condition, curing, transit path length of theultrasonic wave, contact between the transducing transmitter 904 and thetransducing receiver 906, frequency of the transducing transmitter 904and the transducing receiver 906, presence of steel reinforcementperpendicular and parallel to the wave propagation path were all takeninto consideration. Proper coupling was ensured at each stage forrecording readings, and signal shape and strength of received waveformwas monitored during testing, and only sinusoidal waveform was recorded.Furthermore, all tests were conducted on reinforced concrete specimensat 38 days of casting in a temperature-controlled laboratory with atemperature variation of 7.5±3° C.

A tabular representation of a set of readings for a bottom zone of fourconcrete beam samples prior to the application of loading is illustratedin Table 1 provided below.

TABLE 1 UPV readings before loading application using direct method ofinvestigation in neutral condition - bottom zone T (μs) V(m/s) T (μs)V(m/s) T (μs) V(m/s) T (μs) V(m/s) Reading First Second Third FourthLocation Concrete Beam Concrete Beam Concrete Beam Concrete Beam 1 22.46707 22.2 6754 22.7 6614 22.1 6803 2 22.2 6750 22.1 6798 22.5 6656 21.96846 3 22.6 6644 22.4 6691 22.9 6551 22.3 6739 4 22.4 6707 22.2 675422.7 6614 22.1 6803 5 22.4 6707 22.2 6754 22.7 6614 22.1 6803 6 22.46696 23.2 6467 21.7 6912 23.0 6513 7 22.9 6541 22.8 6587 23.2 6466 22.66634 8 21.7 6904 21.6 6953 22.0 6808 22.4 6696 9 22.2 6771 22.0 681922.5 6677 21.8 6868

The set of readings were taken before the application of loading, i.e.,in the neutral condition and served as benchmark to compare readingafter the applied loading. All the reported readings were taken usingthe direct method of testing. Further, the concrete beam samples wereloaded under equal increments of 10% of P_(peak) till failure andreduction in pulse velocity to travel the same path length was recordedusing the direct method of UPV testing. The data provided in Table 1represents the highest pulse velocity corresponding to the lowest (orshortest) transit time recorded for the ultrasonic wave to travel thefixed path length. Readings for the pulse velocity and transit timewider neutral condition for the top zones of the concrete beam samplesare not illustrated in Table 1 for the sake of brevity.

FIG. 11 illustrates a graphical representation 1100 of test results forthe UPV testing method on the concrete beam samples, according toexemplary aspects of the present disclosure. In particular, thegraphical representation 1100 illustrates variation in pulse velocityand transit time before the application of loading under neutralcondition for top and bottom zones. In FIG. 11 , B1-Top refers to thetop zone of the first concrete beam sample, B1-Bottom refers to thebottom zone of the first concrete beam sample, B2-Top refers to the topzone of the second concrete beam sample, B2-Bottom refers to the bottomzone of the second concrete beam sample. B3-Top refers to the top zoneof the third concrete beam sample, B3-Bottom refers to the bottom zoneof the third concrete beam sample, B4-Top refers to the top zone of thefourth concrete beam sample, and B4-Bottom refers to the bottom zone ofthe fourth concrete beam sample.

As can be seen in FIG. 11 , the vertical axis of the test resultrepresents the pulse velocity in m/s and the horizontal axis of therepresents the transit time in μs. From the test results, it is evidentthat average pulse velocity is above the reference pulse velocity (i.e.,above 5000 m/s) indicating a good quality concrete. Further, thevariation in transit time along the length of the steel reinforcementsof the concrete beam samples is 2.1 μs which indicates a good bondcondition.

Further, from the test results, it is evident that for bottom zone thewave transit velocity is slightly faster than the wave transit velocitythrough the top zone. The reason for this can be attributed to thepresence of larger diameter steel reinforcement in the bottom zone,since the ultrasonic wave transits faster through the steelreinforcement and a loss in wave signal strength occurs because of theinterface of steel and concrete, hence the portion of wave that transitsthrough the larger diameter steel reinforcement is larger in the bottomzone as compared to the top zone. It can be seen from the result thatthe variation in the transit time for the top and bottom zone is 2.1 μsand 1.6 μs, respectively, and the velocity for the wave propagation forall zones is above 6500 m/s which indicates a perfect bond condition anda good quality concrete. Since it is known that the ultrasonic pulsetravels 1.4 to 1.7 times faster in steel as compared to concrete hencecorrection factors for two types of steel reinforcements present in thetransit path of the pulse velocity were calculated using the iterativeprocess. These correction factors were chosen as 0.965 for L_(s)/L ratioof 1/5 for steel reinforcement perpendicular to the path of transit and0.92 for L_(s)/L ratio of 1/10 for steel reinforcement parallel to thepath of wave transit corresponding to very good quality concrete withthe reference pulse velocity of 6500 m/s. Further, all testing wasconducted on air dried samples in a temperature-controlled laboratory,and only the stable pulse velocity readings corresponding to sinusoidalwave were recorded.

A tabular representation of a set of readings for the bottom zone offour concrete beam samples after the application of incremental loadingis illustrated in Table 2 provided below.

TABLE 2 UPV readings for bottom zone after the application ofincremental loading measured via the direct method Reading T (μs) V(m/s)T (μs) V(m/s) T (μs) V(m/s) T (μs) V(m/s) Location 0.25 P_(peak) 0.50P_(peak) 0.75 P_(peak) P_(peak) 1 28.0 5355 28.3 5295 29.2 5142 31.634742 2 28.0 5355 28.9 5185 30.4 4939 32.63 4597 3 28.5 5261 29.1 514929.5 5090 33.43 4487 4 29.0 5099 30.1 4978 31.1 4828 34.43 4357 5 30.34889 29.9 4988 34.1 4317 35.83 4186 6 29.4 5100 30.9 4850 31.9 465134.03 4408 7 28.6 5243 29.2 5132 30.3 4955 32.43 4625 8 29.0 5171 28.75221 29.3 5125 31.23 4803 9 27.4 5472 28.8 5203 30.3 4955 30.03 4995

The data provided in Table 2 represents the reduction in pulse velocity(m/s) corresponding to the application of incremental loading measuredvia the direct method of testing.

FIG. 12 illustrates a graphical representation 1200 showing the decreasein the pulse velocity with the increase in the applied loading. As canbe seen in FIG. 12 , as the applied loading increases the pulse velocitystarts to decrease. This can be attributed to the degradation in bondquality of steel reinforcement as the concrete surrounding the steelrefinement starts to crack. Further, although there is a consistentdecrease in the pulse velocity; however, for loadings of 25% of P_(peak)and 50% of P_(peak) the range is almost consistent. As may beunderstood, once the cracks start to develop these cracks do not haveenough length to bridge together and start propagating, however as theloading is increased to 75% of P_(peak) these cracks start bridgingtogether with other cracks in the vicinity which resulted in larger dropin the pulse velocity.

A tabular representation of percentage decrease in the pulse velocitywith respect to increase in applied loading is illustrated in Table 3provided below.

TABLE 3 Percentage reduction in pulse velocity with respect to toneutral condition (bottom zone − direct method) Range of Reduction % %Loading Pulse in Pulse Reduction Reduction Loading Range VelocityVelocity w.r.t Neutral w.r.t P_(peak) Range (%) (m/s) (m/s) (%) (%) (%)Neutral 6953 6467 486 — 34.91  0~25 5472 4889 583 24.40 13.91 25~50 52954900 395 24.23 14.10 50~75 5142 4317 825 33.24 2.50 P_(peak) 4950 4209741 34.91 —

Table 3 presents the percentage decrease in the pulse velocity withrespect to an increase in applied loading. The pulse velocity decreasedby approximately 25% for 25% of P_(peak) and 50% of P_(peak) while alarger drop of 33% and 35% in pulse velocity occurred after theapplication of of P_(peak) and P_(peak). Accordingly, in the ranges of25% of P_(peak) and 50% of P_(peak), the concrete in the vicinity ofsteel reinforcement starts to develop cracks, however these cracks aresmall in length and are not bridged with other adjacent cracks. As theloading is increased to 75% of P_(peak) and P_(peak) these cracks bridgetogether with adjacent cracks and start to propagate resulting in asignificant drop in velocity. FIG. 13 illustrates a graphicalrepresentation 1300 of reduction in pulse velocity along the length ofsteel reinforcement embedded in concrete with an increase in appliedloading in comparison to neutral condition for the bottom zone.

FIG. 14 illustrates a graphical representation 1400 of variation inpulse velocity along the length of steel reinforcement. The nine readinglocations marked along the length of the reinforcement indicate the bondcondition for each incremental loading. As can be seen in FIG. 14 , ateach stage, the pulse velocity continues to decrease with the increasein loading. As can be seen that the third reading location has thehighest drop in pulse velocity owing to crack development in theconcrete surrounding the steel reinforcement, while the seventh readinglocation resulted in the minimum bond degradation depicting lowercracking.

A tabular representation of a set of readings for top zone of concretebeam samples after the application of incremental loading is illustratedin Table 4 provided below.

TABLE 4 UPV readings for top zone after the application of incrementalloading measured via direct method Reading T (μs) V(m/s) T (μs) V(m/s) T(μs) V(m/s) T (μs) V(m/s) Location 0.25 P_(peak) 0.50 P_(peak) 0.75P_(peak) P_(peak) 1 31.5 4766 31.7 4732 31.6 4805 32.2 4701 2 31.3 479231.4 4816 31.7 4773 32.9 4563 3 32.0 4687 31.9 4702 32.2 4695 32.8 45774 31.5 4770 31.3 4797 32.4 4651 32.1 4667 5 31.5 4760 32.1 4677 31.24838 33.1 4536 6 30.6 4903 32.1 4668 31.7 4769 32.5 4620 7 32.3 464331.7 4734 31.5 4769 32.3 4648 8 30.9 4862 31.7 4678 32.9 4574 32.7 45919 31.2 4816 32.1 4668 32.7 4601 33.2 4490

The data presented in Table 4 depicts the reduction in pulse velocitycorresponding to the application of incremental loading measured viadirect method of testing.

FIG. 15 illustrates a graphical representation 1500 of reduction inpulse velocity reading after the application of loading increment forthe top zone. As can be seen from FIG. 15 , as the applied loadingincreases, the pulse velocity starts to reduce. However, after theinitial drop in pulse velocity values, there is gradual reduction invelocity. The presence of cracks coupled with the increase in pulsevelocity and transit time for the same path length indicates thedegradation in bond quality of the embedded steel reinforcement.However, the reduction in pulse velocity for the top zone is lower ascompared to the bottom zone as the top zone experienced less cracking,as compared to the bottom zone.

FIG. 16 illustrates a graphical representation 1600 of variation inpulse velocity after the application of loading. In particular, FIG. 16illustrates reduction in pulse velocity along the length of steelreinforcement embedded in concrete beam samples with increase in appliedloading in comparison to neutral condition for top zone. As shown FIG.16 , there is approximately 22% decrease in pulse velocity for 25% ofP_(peak) followed by 72% and 73% reduction for 50% and 75% of P_(peak)loading application, while the largest drop occurs after the applicationof P_(peak) at 24.5%.

FIG. 17 illustrates a graphical representation 1700 of variation pulsevelocity along the length of steel reinforcement. In particular, FIG. 17illustrates variation in pulse velocity along the length of steelreinforcement embedded in concrete beam samples for top zone with theapplication of incremental loading. From the analysis of the resultsshown in FIG. 17 it is evident that the UPV testing method can be usedto identify the locations of weak bond along the length of steelreinforcement embedded in concrete beam sample. It can be seen from FIG.17 that the maximum drop in pulse velocity occurs at ninth readinglocation along the steel reinforcement.

FIG. 18A illustrates a cross-sectional view 802 of internal cracking ina concrete beam sample, FIG. 18B illustrates a side view 804 of shearcracking in the concrete beam sample, and FIG. 18C illustrates a bottomview 806 of longitudinal cracking in the concrete beam sample, accordingto exemplary aspects of the present disclosure.

FIG. 18D illustrates a cross-sectional view 808 of flexure cracking andbridging of cracks for a concrete beam sample, FIG. 18E illustrates abottom view of bridging of cracks, and FIG. 18F illustrates a side viewof the cracking pattern for the concrete beam sample, according toexemplary aspects of the present disclosure. The reduction in pulsevelocity coupled with the presence of crack bridging as shown in FIGS.18D-18F indicate the degradation in bond condition.

It was observed from the experimentation that as the cracks developed inthe concrete beam samples, the pulse velocity reduced for the same pathlength. The reduction in pulse velocity was used to identify theinitiation, development, and propagation of internal micro-cracks alongthe length of steel reinforcements in the concrete beam samples. Usingthe UPV testing method, areas of bond degradation along the length ofsteel reinforcements embedded in the concrete beam samples could besuccessfully identified. By adopting the direct method for testing forbottom zone, 24.4%, 24.3%, 33.4% and 35% reduction in pulse velocity wasrecorded in comparison to neutral unloaded condition for increase inloading to 25% of P_(peak), 50% of P_(peak), 75% of P_(peak) andP_(peak) respectively. Also, for the top zone, 22%, 21.5%, 23% and 25%reduction in pulse velocity was recorded in comparison to neutralunloaded condition for increase in loading to 25% of P_(peak), 50% ofP_(peak) 75% of P_(peak) and P_(peak) respectively.

Also, based on the bond condition of the concrete beam samples,localized repairs of the concrete beams can be carried out, therebyresulting in the reduction of time, cost, and labor needed forstrengthening or maintenance of the concrete beams. Furthermore, the UPVtesting method can be employed as a stand-alone tool and can also beused in conjunction with other non-destructive tests for increasing theaccuracy of on-site investigation.

In aspects of the present disclosure, a multi-layer feedforward backpropagation perceptron artificial neural network is developed in orderto avoid simplification assumptions for developing models to predict thecracking, owing to the non-linear complex stress distribution at thesteel-concrete interface. The artificial neural network is used topredict the crack width and to conduct sensitivity analysis of thevarious factors influencing the bond deterioration. A high accuracylevel is achieved between the predicted and the experimental values withR2 of 0.97 and the most influential parameter is highlighted.

FIG. 19 depicts the architecture of a feed-forward multilayer perceptronartificial neural network. The network uses back-propagation algorithmlearning process to develop relationship between data, recognizepatterns and works as a black-box model-free tool. Each network iscomposed of multiple layers consisting of an input layer, hiddenlayer/layers and an output layer. Each layer contains severalinterconnected neurons that receive weighted inputs which are summed andpassed through the activation function to produce the single desiredoutput value as shown in FIG. 20 . The activation functions typicallyhave a sigmoidal shape; however, they can adopt non-linear functionalityas well. The general operational mode for the three-layer-feed-forwardback propagation perceptron artificial neural network is as presented inthe below equations.

$\begin{matrix}{I_{I} = {f\left\{ {{{\sum}_{x = 1}^{N}\left( {\Theta_{x,I}.i_{x}} \right)} + b_{I}} \right\}}} & (1)\end{matrix}$ $\begin{matrix}{O_{o} = {f\left\{ {{{\sum}_{x = 1}^{N}\left( {O_{I,O}.H_{I}} \right)} + b_{O}} \right\}}} & (2)\end{matrix}$ $\begin{matrix}{{\psi\left( a_{I} \right)} = \frac{\exp\left( a_{I} \right)}{{\sum}_{x = 1}^{I}{\exp\left( a_{I} \right)}}} & (3)\end{matrix}$

In the above equations, f { } represents the activation function. i_(x)is the normalized input from the neuron at the x^(th) location, I_(I)represents the processing activity at the I^(th) neuron. Whereas O_(o)is the output processing activity at the output neuron. O_(x,I) andO_(I,o) are the weightages on the connections at the I^(th) input neuronand O^(th) output neuron respectively while b_(I) and b_(o) are theweighted biases at the input and output neurons. An ANN can consist ofseveral hidden layers. All the neurons in the layers are interconnectedas shown in FIG. 19 . The role of weighted biases on the hidden andinput neurons is to allow for achieving the desired weightages at theoutput value. The value of these biases ranges from 1 to any suitableconstant among the connected layers. The IBM SPSS (2017) package wasadopted for statistical analysis and neural network whileback-propagation was adopted to conduct supervised training of the ANN.A softmax function as shown in (3) was employed to transform real-valuedarguments to 0 to 1 and summation of 1 as an activation function in theoutput layer. Softmax is a mathematical function used for converting avector of number into probability vectors with proportionality to thescale of each value in the vector. This function is applied in machinelearning as the activation function since ANN requires an activationfunction in the output layer for making prediction. This is especiallyneeded for a network configured towards N output values, one for eachclass in a classification task. This function normalizes the outputs,from the weighted sums to the probabilities which add to one. This valueis further interpreted as probability of membership for each class ofmembers. Since ANNs rely upon random number generators forinitialization of weightages and sample selection, this can lead toerroneous output from the network on each run-cycle. Hence large numberof training run cycles are needed to train the ANN in order to achievedesired results within the allowed tolerances.

FIG. 21 presents the flow-diagram of the feed-forward artificialmulti-layer perceptron neural network. The process begins by selectingthe number of hidden layers and number of neurons per layer using atrial and error approach. Since large numbers of input variable can leadto an inefficient neural network with increased probability ofoverfitting, a conscious effort was made to keep the input variable low.In this regards, factors which are hard to obtain from old builtstructures were consciously eradicated from the model in order to avoidoverfitting. Hence, parameters of water-cement ratio, cement content,type of additives, slump, air entrainment content, initial concretetemperature, ambient air temperature, curing time were not taken intoconsideration in the model as gathering this type of data would beimmensely difficult for field operation teams. Each pre-processed dataset was subdivided into three groups: a training, a testing and ahold-out dataset. 60%, 25% and 15% values respectively of data wereselected for training, testing and holdout. The holdout data set wasused for validation of the developed ANN. 100,000 cycles or a toleranceof was used cut-off condition for termination of the simulation runs.Once the optimum ANN architecture was selected, the network was saved,and further parametric analysis was conducted using the developed ANN.In the present disclosure, the feed-forward multi-layer perception(FFMLP) consists of four input variables as a function of crack width.The ANN employs a novel approach of using material and mechanicalfactors for predicting the crack width as compared to past researchwork. These variables consist of the compressive strength of concrete,f_(c)′, the ultrasonic pulse velocity (UPV) to transit the fixed pathlength, the concrete cover to reinforcement bar ratio (cc/d), and thepath length for the ultrasonic pulse to transit (PL). Each of thesevariables were considered in the developed ANN as shown in FIG. 22 . Thearchitecture of the FFMLP consisted of four neurons in the input layer,three neurons in the hidden layer and one neuron the output layerleading to a FFMLP-4-3-1 network. Pearson's correlation coefficient ofFFMLP was achieved as Table 6 presents the weightage, biases andinfluence importance of parameters of FFMLP-4-3-1 artificial neuralnetwork.

TABLE 6 Weightage, Biases and Influence Importance of parameters ofFFMLP-4-3-1 Artificial Neural Network Hidden Input Layer Output Layerfc′ UPV cc/d PL Layer Bias −0.8419 −2.7861 −3.0199 5.4072 −0.7542 1−0.1893 1.0491 4.7419 −6.6679 −7.9770 2 0.7473 −0.0929 0.8007 0.1442−11.081 3 −9.8617 4.3111 −17.611 −19.074 2.3372 4 4.8301 −0.6444 11.5002.7793 9.1120 Imp. % 43.91 21.17 19.08 15.84

FIG. 23 presents the normalized importance of the influence variableused in the presented study. From the result, it is evident thatconcrete compressive strength, f_(c)′, has the highest influence on thebond performance of steel reinforcement embedded in the concretefollowed by UPV. Ample concrete cover (cc/d) mandatory for bonddevelopment as reduction in cover leads to lower bond performance andcracking at the steel-concrete interface, while the path length for theultrasonic pulse velocity has the least influence on the bondcharacteristics. Experimental evidence by past researchers (See: NolanC. and Andres, W. (2019). “Investigation of the effects of corrosion onbond strength of steel in concrete using neural network”. The 2019 WorldCongress on Advances in Structural Engineering and Mechanics (ASEM19)Jeju Island. Korea, Sep. 17-21, 2019; Hakim, S. and Abdul Razak, H.(2014). “Modal parameters based structural damage detection usingartificial neural networks—a review”. Smart Structures and Systems, AnInt'l Journal, 14(2), 159-189, DOI: hypertext transfer protocol://dx.doi.org/10.12989/sss.2014.14.2.159) have shown that micro-crackdevelopment at the steel-concrete interface reduces the UPV. Hence, theabove findings are inconsistence with the past research.

A parametric sensitivity influence analysis was conducted in order toinvestigate of the effect of these parameters in isolation with regardsto other parameters. The objective of this analysis was to identify theinfluence of each parameter in isolation with other. For this purpose,variation in various parameters were investigated using the FFMPL-4-3-1ANN by isolating a parameter and evaluating its effect of otherindicators. For this purpose, FIG. 24 indicates the variation inconcrete strength with respect to UPV. It can be noted that as theconcrete strength increase the UPV increases, indicating a better bondcondition. This finding further validates the observation that delay inultrasonic pulses transiting the same path length can be related to thepresence of micro-cracks at the steel-concrete interface, thus leadingto a lower bond quality. Furthermore, FIG. 25 depicts the comparisonbetween the experimental crack width and the predicted crack width byFFMPL-4-3-1 ANN. This results proves that the ANN model is successful inpredicting the crack width. The training, and validation phases of theANN produced favorable results. In the training phase, 77% of thepredicted results were within the accuracy threshold limit of 15% withan error of 16.17%. In the validation phase, 86% predicted values werewithin the threshold limit with maximum and minimum error of 12.24% and0.03% respectively. Therefore, the FFMLP-4-3-1 ANN is successful intaking into consideration the complex interaction of parameters thatinfluence the bond performance of the beam element and is successful inpredicting the crack width. A good agreement is found between theexperimental and the predicted results by the FFMLP-4-3-1 ANN.

It is understood that the examples, embodiments, and teachings presentedin the present disclosure are described merely for illustrativepurposes. Any variations or modifications thereof are to be includedwithin the scope of the present disclosure as discussed.

The first embodiment is illustrated with respect to FIGS. 1-18F. Thefirst embodiment describes a method for non-destructive testing of abond condition of concrete beams reinforced by steel rods. The methodincludes applying, by a transmitting transducer of an ultrasonic tester,ultrasonic pulses to a concrete beam; receiving, by a receivingtransducer, vibrational waves reflected from the steel rods at aplurality of reading locations along the concrete beam; measuring atransit time of the vibrational waves received at each reading location;determining a pulse velocity of each vibrational wave received at eachreading location; determining a highest pulse velocity of thevibrational waves at each reading location; comparing the highest pulsevelocity of the vibrational waves received at a reading location to afirst reference pulse velocity; and identifying a bond condition ofcracking around a steel rod at a testing location when the highest pulsevelocity at the testing location is less than the first reference pulsevelocity.

The method further includes determining the pulse velocity of avibrational wave at each reading location by dividing a distance of thereceiving transducer from the reading location by the transit time.

The method further includes determining a peak load carrying capacity(P_(peak)) of the concrete beam by applying a force perpendicular to acenter of a length of the concrete beam; applying ultrasonic pulses tothe concrete beam; determining a highest pulse velocity at each readinglocation; increasing a magnitude of the force by increments; determininga highest pulse velocity at each reading location for each incrementalincrease in the magnitude of the force; and determining the P_(peak), ofthe concrete beam when the highest pulse velocity at one of the readinglocations is less than a second reference pulse velocity.

The method comprises predicting, by an artificial neural network, awidth of each crack formed around the bonds in the concrete.

The method further includes marking the concrete beam with a grid havingtwo rows and a plurality of columns; wherein an intersection of a rowwith a column defines a reading location.

A first row is parallel to and separated from a second row by a distancein the range of 140 mm to 160 mm; and each column is parallel anadjacent column and separated from the adjacent column by a distance inthe range of 90 mm to 110 mm.

The method further includes determining the first reference pulsevelocity at each reading location by measuring, the highest pulsevelocity when the force applied to the concrete beam is zero.

The method further includes determining the second reference pulsevelocity at each reading location by measuring the highest pulsevelocity when the force applied to the concrete beam is 75% of the peakload carrying capacity.

The method further includes marking the reading locations on a first rowparallel to a length of a first steel rod within the concrete beam; andmarking the reading locations on a second row parallel to a length of asecond steel rod within the concrete beam.

The method further includes attaching the ultrasonic receiver to theconcrete beam at a location perpendicular to a length of the steel rods;and contacting the transmitting transducer to the concrete beam at eachof the plurality of reading locations.

The second embodiment is illustrated with respect to FIGS. 1-18F. Thesecond embodiment describes a non-destructive ultrasonic testing methodof a bond condition of a concrete beam reinforced by steel rods. Thenon-destructive ultrasonic testing method includes applying, by atransmitting transducer of an ultrasonic tester, ultrasonic pulses to aconcrete beam; receiving, by a receiving transducer, vibrational wavesreflected from the steel rods at a plurality of reading locations alongthe concrete beam; measuring a transit time of the vibrational wavesreceived at each reading location; determining a pulse velocity of eachvibrational wave received at each reading location; determining ahighest pulse velocity of the vibrational waves at each readinglocation, the highest pulse velocity at each reading location defining afirst reference pulse velocity at the reading location; determining apeak load carrying capacity (P_(peak)) of the concrete beam by applyinga force perpendicular to a center of a length of the concrete beam;applying a second set of ultrasonic pulses to the concrete beam;measuring a highest pulse velocity at each reading location receivedfrom the second set of ultrasonic pulses; increasing a magnitude of theforce by increments; measuring a highest pulse velocity at each readinglocation for each incremental increase in the magnitude of the force;and determining the P_(peak) of the concrete beam when the highest pulsevelocity at one of the reading locations is less than a second referencepulse velocity, wherein the second reference pulse velocity is less thanthe first reference pulse velocity.

The non-destructive ultrasonic testing method further includesdetermining the pulse velocity of a vibrational wave at each readinglocation by dividing a distance of the receiving transducer from thereading location by the transit time.

The non-destructive ultras testing method further includes determiningthe second reference pulse velocity at each reading location bymeasuring the highest pulse velocity when the force applied to theconcrete beam is 75% of the peak load carrying capacity.

The non-destructive ultrasonic testing method further includes comparingthe highest pulse velocity of the vibrational waves received at areading location to the second reference pulse velocity; and identifyinga bond condition of cracking around a steel rod at a testing locationwhen the highest pulse velocity at the testing location is less than thesecond reference pulse velocity.

The non-destructive ultrasonic testing method further includes markingthe concrete beam with a grid having two rows and a plurality ofcolumns; wherein an intersection of a row with a column defines areading location.

The non-destructive ultrasonic testing method further includesperforming an ultrasonic velocity test of the concrete beam by attachingthe ultrasonic receiver to the concrete beam at a location perpendicularto a length of the steel rods; and contacting the transmittingtransducer to the concrete beam at each of the plurality of readinglocations.

The third embodiment is illustrated with respect to FIGS. 1-18F. Thethird embodiment describes a system for non-destructive testing, of abond condition of concrete beams reinforced by steel rods. The systemfor the non-destructive testing includes a transducing transmitter; atransducing receiver; an ultrasonic pulse generator configured togenerate drive signals for the transducing transmitter and receive aplurality vibrational waves at the transducing receiver; a computingdevice including: a measurement circuit configured to record a transittime for each vibrational wave and divide a distance between thetransducing transmitter and the transducing receiver by the transit timeto determine a pulse velocity of each vibrational wave; a comparisoncircuit configured to identify a highest pulse velocity of thevibrational waves and compare each highest pulse velocity to a firstreference pulse velocity; and a decision circuit configured to identifya compromised bond condition around a steel rod when the highest pulsevelocity is less than the first reference pulse velocity.

The system for non-destructive testing further includes a peak loadtesting device including a first support configured to support a firstbottom end of the concrete beam; a second support configured to supporta second bottom end of the concrete beam; a force applicator configuredto provide a variable force to a top center of the concrete beam; andwherein the computing device is further configured to recordmeasurements of the pulse velocities at a plurality of reading locationsfor each change in the variable force and identify an amplitude of thevariable force at which the highest pulse velocity is less than a secondreference pulse velocity, wherein the second reference pulse velocityindicates a bond condition of cracking of the concrete around a steelrod.

The system for non-destructive testing further includes determining thesecond reference pulse velocity at each reading location by measuringthe highest pulse velocity when the force applied to the concrete beamis 75% of a peak load carrying capacity.

FIG. 26 is an illustration of a non-limiting example of details ofcomputing hardware used in the computing system, according to exemplaryaspects of the present disclosure. In FIG. 26 , a controller 2600 isdescribed which is a computing device (for example, computing device108) and includes a CPU 2601 which performs the processes describedabove/below. The process data and instructions may be stored in memory2602. These processes and instructions may also be stored on a storagemedium disk 2604 such as a hard drive (HDD) or portable storage mediumor may be stored remotely.

Further, the claims are not limited by the form of the computer-readablemedia on which the instructions of the inventive process are stored. Forexample, the instructions may be stored on CDs, DVDs, in FLASH memory,RAM, ROM, PROM, EPROM, EEPROM, hard disk or any other informationprocessing device with which the computing device communicates, such asa server or computer.

Further, the claims may be provided as a utility application, backgrounddaemon, or component of an operating system or combination thereofexecuting in conjunction with CPU 2601, 2603 and an operating systemsuch as Microsoft Windows 7, UNIX, Solaris, LINUX, Apple MAC-OS andother systems known to those skilled in the art.

The hardware elements in order to achieve the computing device may berealized by various circuitry elements, known to those skilled in theart. For example, CPU 2601 or CPU 2603 may be a Xenon or Core processorfrom Intel of America or an Opteron processor from AMD of America, ormay be other processor types that would be recognized by one of ordinaryskill in the art. Alternatively, the CPU 2601, 2603 may be implementedon an FPGA, ASIC, PLD or using discrete logic circuits, as one ofordinary skill in the art would recognize. Further, CPU 2601, 2603 maybe implemented as multiple processors cooperatively working in parallelto perform the instructions of the inventive processes described above.

The computing device in FIG. 26 also includes a network controller 2606,such as an Intel Ethernet PRO network interface card from IntelCorporation of America, for interfacing with network 2660. As can beappreciated, the network 2660 can be a public network, such as theInternet, or a private network such as an LAIN or WAN network, or anycombination thereof and can also include PSTN or ISDN sub-networks. Thenetwork 2660 can also be wired, such as an Ethernet network, or can bewireless such as a cellular network including EDGE, 3G and 4G wirelesscellular systems. The wireless network can also be WiFi, Bluetooth, orany other wireless form of communication that is known.

The computing device further includes a display controller 2608, such asa NVIDLA GeForce GTX or Quadro graphics adaptor from NVIDIA Corporationof America for interfacing with display 2610, such as a Hewlett PackardHPL2445w LCD monitor. A general purpose I/O interface 2612 interfaceswith a keyboard and or mouse 2614 as well as a touch screen panel 2616on or separate from display 2610. General purpose I/O interface alsoconnects to a variety of peripherals 2618 including printers andscanners, such as an OfficeJet or DeskJet from Hewlett Packard.

A sound controller 2620 is also provided in the computing device such asSound Blaster X-Fi Titanium from Creative, to interface withspeakers/microphone 2622 thereby providing sounds and/or music.

The general-purpose storage controller 2624 connects the storage mediumdisk 2604 with communication bus 2626, which may be an ISA, EISA, VESA,PCI, or similar, for interconnecting all of the components of thecomputing device. A description of the general features andfunctionality of the display 2610, keyboard and/or mouse 2614. as wellas the display controller 2608, storage controller 2624, networkcontroller 2606, sound controller 2620, and general purpose I/Ointerface 2612 is omitted herein for brevity as these features areknown.

The exemplary circuit elements described in the context of the presentdisclosure may be replaced with other elements and structureddifferently than the examples provided herein. Moreover, circuitryconfigured to perform features described herein may be implemented inmultiple circuit units (e.g., chips), or the features may be combined incircuitry on a single chipset, as shown on FIG. 27 .

FIG. 27 shows a schematic diagram of a data processing system 2700 usedwithin the computing system, according to exemplary aspects of thepresent disclosure. The data processing system 2700 is an example of acomputer in which code or instructions implementing the processes of theillustrative aspects of the present disclosure may be located.

In FIG. 27 , data processing system 2730 employs a hub architectureincluding a north bridge and memory controller hub (NB/MCH) 2725 and asouth bridge and input/output (I/O) controller hub (SB/ICH) 2727. Thecentral processing unit (CPU) 2730 is connected to NB/MCH 2775. TheNB/MCH 2725 also connects to the memory 2745 via a memory bus, andconnects to the graphics processor 2750 via an accelerated graphics port(AGP). The NB/MCH 2725 also connects to the SB/ICH 2727 via an internalbus (e.g., a unified media interface or a direct media interface). TheCPU Processing unit 2730 may contain one or more processors and even maybe implemented using one or more heterogeneous processor systems.

For example, FIG. 28 shows one aspects of the present disclosure of CPU2730. In one aspect of the present disclosure, the instruction register2838 retrieves instructions from the fast memory 2840. At least part ofthese instructions is fetched from the instruction register 2838 by thecontrol logic 2836 and interpreted according to the instruction setarchitecture of the CPU 2730. Part of the instructions can also bedirected to the register 2832. In one aspects of the present disclosurethe instructions are decoded according to a hardwired method, and inanother aspects of the present disclosure the instructions are decodedaccording a microprogram that translates instructions into sets of CPUconfiguration signals that are applied sequentially over multiple clockpulses. After fetching, and decoding the instructions, the instructionsare executed using the arithmetic logic unit (ALU) 2834 that loadsvalues from the register 2832 and performs logical and mathematicaloperations on the loaded values according to the instructions. Theresults from these operations can be feedback into the register and/orstored in the fast memory 2840. According, to certain aspects of thepresent disclosures, the instruction set architecture of the CPU 2730can use a reduced instruction set architecture, a complex instructionset architecture, a vector processor architecture, a very largeinstruction word architecture.

Furthermore, the CPU 2730 can be based on the Von Neuman model or theHarvard model. The CPU 2730 can be a digital signal processor, an FPGA,an ASIC, a PLA, a PLD, or a CPLD. Further, the CPU 2730 can be an x86processor by Intel or by AMD; an ARM processor, a Power architectureprocessor by, e.g., IBM; a SPARC architecture processor by SunMicrosystems or by Oracle; or other known CPU architecture.

Referring again to FIG. 27 , the data processing system 2730 can includethat the SB/ICH 2727 is coupled through a system bus to an I/O Bus, aread only memory (ROM) 2756, universal serial bus (USB) port 2764, aflash binary input/output system (BIOS) 2768, and a graphics controller2758. PCI/PCIe devices can also be coupled to SB/ICH 2727 through a PCIbus 2762.

The PCI devices may include, for example, Ethernet adapters, add-incards, and PC cards for notebook computers. The Hard disk drive 2760 andCD-ROM 2756 can use, for example, an integrated drive electronics (IDE)or serial advanced technology attachment (SATA) interface. In oneaspects of the present disclosure the I/O bus can include a super I/O(SIO) device.

Further, the hard disk drive (HDD) 2760 and optical drive 2766 can alsobe coupled to the SB/ICH 2727 through a system bus. In one aspects ofthe present disclosure, a keyboard 2770, a mouse 2772, a parallel port2778, and a serial port 2776 can be connected to the system bus throughthe I/O bus. Other peripherals and devices that can be connected to theSB/ICH 2727 using a mass storage controller such as SATA or PATA, anEthernet port, an ISA bus, an LPC bridge, SMBus, a DMA controller, andan Audio Codec.

Moreover, the present disclosure is not limited to the specific circuitelements described herein, nor is the present disclosure limited to thespecific sizing and classification of these elements. For example, theskilled artisan will appreciate that the circuitry described herein maybe adapted based on changes on battery sizing and chemistry, or based onthe requirements of the intended back-up load to be powered.

The functions and features described herein may also be executed byvarious distributed components of a system. For example, one or moreprocessors may execute these system functions, wherein the processorsare distributed across multiple components communicating in a network.The distributed components may include one or more client and servermachines, which may share processing, as shown by FIG. 29 , in additionto various human interface and communication devices (e.g., displaymonitors, smart phones, tablets, personal digital assistants (PDAs)).The network may be a private network, such as a LAN or WAN, or may be apublic network, such as the Internet. Input to the system may bereceived via direct user input and received remotely either in real-timeor as a batch process. Additionally, some aspects of the presentdisclosures may be performed on modules or hardware not identical tothose described. Accordingly, other aspects of the present disclosuresare within the scope that may be claimed. The above-described hardwaredescription is a non-limiting example of corresponding structure forperforming the functionality described herein.

Obviously, numerous modifications and variations of the presentdisclosure are possible in light of the above teachings. It is thereforeto be understood that within the scope of the appended claims, thedisclosure may be practiced otherwise than as specifically describedherein.

1. Concrete beam testing method, comprising: casting a Portland cementaround steel reinforcements and curing to form a concrete beam withsteel reinforcements: applying, by a transmitting transducer of anultrasonic tester, ultrasonic pulses to the concrete beam with steelreinforcements, wherein the transmitting transducer operates at afrequency of from 20 kHz to 150 kHz; receiving, by a receivingtransducer, vibrational waves reflected from the steel rods at aplurality of reading locations along the concrete beam; measuring atransit time of the vibrational waves received at each reading location;determining a pulse velocity of each vibrational wave received at eachreading location: determining a highest pulse velocity of thevibrational waves at each reading location; comparing the highest pulsevelocity of the vibrational waves received at a reading location to afirst reference pulse velocity; and identifying a bond condition ofcracking around a steel rod at a testing location when the highest pulsevelocity at the testing location is less than the first reference pulsevelocity: determining a peak load carrying capacity (P_(peak)) of theconcrete beam by: applying a force perpendicular to a center of a lengthof the concrete beam; applying ultrasonic pulses to the concrete beam;determining the highest pulse velocity at each reading location;increasing a magnitude of the force by equal increments of 10%;determining the highest pulse velocity at each reading location for eachincremental increase in the magnitude of the force; and. determining thepeak load carrying capacity (P_(peak)) of the concrete beam when thehighest pulse velocity at one of the reading locations is less than asecond reference pulse velocity.
 2. The method of claim 1, wherein thevibrational waves reflected from the steel reinforcements in theconcrete beam are received with the receiving transducer operating at afrequency of 60 kHz.
 3. The method of claim 1, wherein the ultrasonicpulses applied to the concrete beam have a pulse velocity of from 4950to 5472 m/s.
 4. The method of claim 1, further comprising predicting,lid, an artificial neural network, a width of each crack formed aroundthe bonds in the concrete beam. cm
 5. The method of claim 1, furthercomprising: marking the concrete beam with a grid haying two rows and aplurality of columns; wherein an intersection of a row with a columndefines a reading location.
 6. The method of claim 5, wherein: a firstrow is parallel to and separated from a second row by a distance in therange of 140 mm to 160 mm; and each column is parallel to an adjacentcolumn and separated from the adjacent column by a distance in the rangeof 90 mm to 110 mm.
 7. The method of claim 5, further comprising:determining the first reference pulse velocity at each reading locationby measuring the highest pulse velocity when the force applied to theconcrete beam is zero.
 8. (canceled).
 9. The method of claim 5, furthercomprising: marking the reading locations on a first row parallel to alength of a first steel rod reinforcement within the concrete beam; andmarking the reading locations on a second row parallel to a length of asecond steel rod reinforcement within the concrete beam.
 10. The methodof claim 1, further comprising: attaching the receiving transducer tothe concrete beam at a location perpendicular to a length of the steelreinforcements; and contacting the transmitting transducer to theconcrete beam at each of the plurality of reading locations. 11-20.(canceled).